A comprehensive review revealed significant advances in food allergy diagnostics while highlighting persistent challenges in achieving accurate, timely diagnoses.

The review, authored by Holly Boyd, MBBS MSc, and Alexandra F. Santos, MD, PhD, from King's College London, detailed how emerging diagnostic tools such as the basophil activation test (BAT) and epitope-specific IgE testing are transitioning into clinical practice, potentially reducing reliance on oral food challenges (OFCs).

"The ability to differentiate patients with an allergy from those who are sensitized but do not have an allergy remains a significant challenge in FA [food allergy] diagnosis, particularly when testing for less common allergens in cases in which predictive values are unknown," the investigators wrote in the Journal of Allergy and Clinical Immunology.

They emphasized that while OFCs remain the diagnostic gold standard, they are resource-intensive and pose risks of allergic reactions. Current wait times for OFCs often exceed capacity, resulting in delayed diagnoses and prolonged food avoidance that may increase sensitization risk, especially in young children.

Among the promising emerging diagnostics, the BAT has demonstrated particular utility. The European Academy of Allergy and Clinical Immunology now recommends the BAT to support food allergy diagnosis. In peanut allergy studies specifically, the BAT has achieved up to 96% specificity in identifying clinically reactive vs tolerant individuals.

The review also highlighted novel approaches under investigation, including:

• Epitope-based testing that identifies IgE antibodies binding to specific antigenic sites
• The mast cell activation test, which uses patient plasma to sensitize mast cells
• T-cell profiling to differentiate clinical phenotypes
• Alternative biological sampling methods including buccal swabs, saliva, and stool
• Machine learning algorithms to integrate multiple test results and clinical information.

However, the researchers noted that many of these emerging diagnostics face implementation challenges, including limited availability, higher costs, and the need for specialized equipment and expertise.

Future improvements in food allergy diagnosis will likely come from combining multiple diagnostic approaches rather than relying on single tests. The researchers emphasized that the conscientious use of existing tests increased access to superior diagnostic tools, and strategic test combinations could enhance diagnostic precision while reducing unnecessary OFCs.

"The overall goal is to enhance the precision of FA diagnosis, thereby enabling the timely introduction of tolerated foods into patients' diets," they concluded.

The authors reported funding from multiple sources including the Medical Research Council, Food Allergy Research and Education, and the National Institute of Allergy and Infectious Diseases. Full disclosures can be found in the study.